Cascade regulation of the toluene-3-monooxygenase operon (tbuA1UBVA2C) of Burkholderia pickettii PKO1: role of the tbuA1 promoter (PtbuA1) in the expression of its cognate activator, TbuT

Byrne, Armando M.; Olsen, Ronald H.

doi:10.1128/jb.178.21.6327-6337.1996

Cited by 60 publications

(66 citation statements)

References 47 publications

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“…The genes for TbuT and TouR are located downstream of the target operons tbuA1UBVA2C and touABCDEF, respectively, but are transcribed in the same direction (11,22). Expression of tbuT is partly controlled by TbuT itself, since a transcript covering both the tbu structural genes and tbuT is synthesized in the presence of toluene, which starts at the TbuT-dependent promoter P tbuA1 (22). Also, areR is transcribed in the same direction as areCBA but is located upstream of it.…”

Section: Catabolic Operons Controlled By Xylr/dmpr Subclass Regulatorsmentioning

confidence: 99%

Bacterial Transcriptional Regulators for Degradation Pathways of Aromatic Compounds

Tropel

Meer

2004

Microbiol Mol Biol Rev

343

338

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Human activities have resulted in the release and introduction into the environment of a plethora of aromatic chemicals. The interest in discovering how bacteria are dealing with hazardous environmental pollutants has driven a large research community and has resulted in important biochemical, genetic, and physiological knowledge about the degradation capacities of microorganisms and their application in bioremediation, green chemistry, or production of pharmacy synthons. In addition, regulation of catabolic pathway expression has attracted the interest of numerous different groups, and several catabolic pathway regulators have been exemplary for understanding transcription control mechanisms. More recently, information about regulatory systems has been used to construct whole-cell living bioreporters that are used to measure the quality of the aqueous, soil, and air environment. The topic of biodegradation is relatively coherent, and this review presents a coherent overview of the regulatory systems involved in the transcriptional control of catabolic pathways. This review summarizes the different regulatory systems involved in biodegradation pathways of aromatic compounds linking them to other known protein families. Specific attention has been paid to describing the genetic organization of the regulatory genes, promoters, and target operon(s) and to discussing present knowledge about signaling molecules, DNA binding properties, and operator characteristics, and evidence from regulatory mutants. For each regulator family, this information is combined with recently obtained protein structural information to arrive at a possible mechanism of transcription activation. This demonstrates the diversity of control mechanisms existing in catabolic pathways

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Section: Catabolic Operons Controlled By Xylr/dmpr Subclass Regulatorsmentioning

confidence: 99%

Bacterial Transcriptional Regulators for Degradation Pathways of Aromatic Compounds

Tropel

Meer

2004

Microbiol Mol Biol Rev

343

338

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“…This biosensor was constructed by creating a transcriptional fusion between gfp and the toluene-benzene utilization (tbu) pathway promoter (PtbuA1) of Ralstonia pickettii PKO1. The tbu operon encodes a toluene-3-monooxygenase, and the pathway has a broad effector range, including many monosubstituted benzene derivatives and trichloroethylene (TCE) (5,26). The biosensor strain also contained the PtbuA1 promoter transcriptional activator (TbuT) fused to the constitutive neomycin phosphotransferase (PnptII) promoter that was carried on a broadhost-range promoter probe vector (24,25).…”

mentioning

confidence: 99%

Development and Characterization of a Green Fluorescent Protein-Based Bacterial Biosensor for Bioavailable Toluene and Related Compounds

Stiner

Halverson

2002

Appl Environ Microbiol

132

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A green fluorescent protein-based Pseudomonas fluorescens strain A506 biosensor was constructed and characterized for its potential to measure benzene, toluene, ethylbenzene, and related compounds in aqueous solutions. The biosensor is based on a plasmid carrying the toluene-benzene utilization (tbu) pathway transcriptional activator TbuT from Ralstonia pickettii PKO1 and a transcriptional fusion of its promoter PtbuA1 with a promoterless gfp gene on a broad-host-range promoter probe vector. TbuT was not limiting, since it was constitutively expressed by being fused to the neomycin phosphotransferase (nptII) promoter. The biosensor cells were readily induced, and fluorescence emission after induction periods of 3 h correlated well with toluene, benzene, ethylbenzene, and trichloroethylene concentrations. Our experiments using flow cytometry show that intermediate levels of gfp expression in response to toluene reflect uniform induction of cells. As the toluene concentration increases, the level of gfp expression per cell increases until saturation kinetics of the TbuTPtbuA1 system are observed. Each inducer had a unique minimum concentration that was necessary for induction, with K app values that ranged from 3.3 ؎ 1.8 M for toluene to 35.6 ؎ 16.6 M for trichloroethylene (means ؎ standard errors of the means), and maximal fluorescence response. The fluorescence response was specific for alkyl-substituted benzene derivatives and branched alkenes (di-and trichloroethylene, 2-methyl-2-butene). The biosensor responded in an additive fashion to the presence of multiple inducers and was unaffected by the presence of compounds that were not inducers, such as those present in gasoline. Flow cytometry revealed that, in response to toxic concentrations of gasoline, there was a small uninduced population and another larger fully induced population whose levels of fluorescence corresponded to the amount of effectors present in the sample. These results demonstrate the potential for green fluorescent protein-based bacterial biosensors to measure environmental contaminants.

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“…BphR is similar to various regulators that control expression of genes involved in catabolism of toluene [7,28], phenol ( [1,24,37,39,46]; Takeo, unpublished), phenanthrene, 1,2,4-trimethylbenzene, m-and p-xylene [14], naphthalene [41], and 2-hydroxy-biphenyl (Schmid and van der Meer, unpublished). Each of these regulators belongs to the NtrC family of transcriptional activators which typically activate expression of genes from promoters recognized by core RNA polymerase associated with the alternative sigma-54 factor.…”

Section: Analysis Of Intergenic Sequences Of Pnl1mentioning

confidence: 99%

Induction of aromatic catabolic activity in Sphingomonas aromaticivorans strain F199

Romine

Fredrickson

1999

Journal of Industrial Microbiology and Biotechnology

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Enzyme induction studies with Sphingomonas aromaticivorans F199 demonstrated that both toluene and naphthalene induced expression of both naphthalene and toluene catabolic enzymes. However, neither aromatic compound induced expression of all the enzymes required for complete mineralization of either naphthalene or toluene. Activity measurements in combination with gene sequence analyses indicate that growth on either aromatic substrate in the absence of the other is, therefore, sub-optimal and is predicted to lead to the build-up of metabolites due to imbalance in toluene or naphthalene catabolic enzyme activities. Growth on toluene may be further inhibited by the co-expression of two toluene catabolic pathways, as predicted from gene sequence analyses. One of these pathways may potentially result in the formation of a dead-end intermediate, possibly benzaldehyde. In contrast, either pcresol or benzoate can support high levels of growth. Analyses of promoter region sequences on the F199 aromatic catabolic plasmid, pNL1, suggest that additional regulatory events are modulated through the interaction of BphR with Sigma54 type promoters and through the binding of a regulator upstream of p-cresol catabolic genes and xylM. We hypothesize that the unusual gene clustering in strain F199 is optimized for simultaneous degradation of multiple aromatic compound classes, possibly in response to the heterogeneous composition of aromatic structures in the fossil organic matter present in the deep Atlantic Coastal Plain sediments from which this bacterium was isolated.

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Cascade regulation of the toluene-3-monooxygenase operon (tbuA1UBVA2C) of Burkholderia pickettii PKO1: role of the tbuA1 promoter (PtbuA1) in the expression of its cognate activator, TbuT

Cited by 60 publications

References 47 publications

Bacterial Transcriptional Regulators for Degradation Pathways of Aromatic Compounds

Bacterial Transcriptional Regulators for Degradation Pathways of Aromatic Compounds

Development and Characterization of a Green Fluorescent Protein-Based Bacterial Biosensor for Bioavailable Toluene and Related Compounds

Induction of aromatic catabolic activity in Sphingomonas aromaticivorans strain F199

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